Interferon therapy for hepatitis C

A case of a patient infected with a hepatitis C virus genotype 3a multidrug resistant variant in Pakistan

BACKGROUND

Approximately 10 million people in Pakistan are infected with the hepatitis C virus (HCV). Most patients develop chronic hepatitis, with rare cases of spontaneous clearance. However, little is known about multidrug resistant viral variants in Pakistan.

FINDINGS

This case study describes a 47-year-old male diagnosed with chronic HCV genotype 3a infection in 2003. After an initial diagnosis of viral infection, the patient remained treatment naïve for 5 years. He received two therapy cycles of interferon (IFN) plus ribavirin (RBV) in 2007 and 2010, however, he was non-responsive to the therapy. The patient then received an additional two treatment cycles of pegylated IFN α-2b plus RBV (in 2011 and 2013); he was still non-responsive. In 2016, the patient underwent sofosbuvir plus RBV combination therapy, however, the sustained virological response was still not achieved. The host genetic factor was found to be heterozygous guanine and thymine (GT) and cytosine and thymine (CT) genotypes of rs8099917 and rs12979860 polymorphism of IL28B, respectively. Phylogenetic analysis suggests that the resistant variant belong to an out-group and may require triple therapy.

CONCLUSIONS

This is the first case that reports on a HCV-infected individual who was a non-responder to multiple IFN therapies in Pakistan. Further studies are needed to understand multidrug-resistant HCV variants in the Pakistani population.

A DNA hybridization method for typing hepatitis C virus genotype 2c

A high prevalence of hepatitis C virus (HCV) genotype 2c (22%) was detected in sera from 459 italian patients by core-region amplification and hybridization with specific probes by DNA enzyme immunoassay. Amplified fragments failed to hybridize with 1a, 1b, 2a, 2b and 3a subtype-specific and 4, 5, 6 type-specific oligonucleotides in 105 patients. Hybridization of these samples with type 2 probe, which recognized all the subtypes sequences, showed evidence for genotype 2 distinct from 2a and 2b. Fourteen out of these 105 isolates were cloned and sequenced. The results were consistent with genotyping assay. Nucleotide sequences were partially related to types 2a, 2b, 2d, 2e and 2f (87.0-93.5% of identity). The average nucleotide identity was highest for genotype 2c (95.87%). On the basis of sequence analysis, subtype 2c specific probe was derived. Hybridization efficiency with the newly designed probe was very high and more than 95% (100/105) of type 2 cases were classified as 2c. Evidence of different outcome of therapy inside the same HCV major type account for the need of accurate subtyping. In this study, amplification of the core region followed by hybridization with highly specific probes enabled distinction between HCV subtypes.

Mixed cryoglobulinemia secondary to hepatitis C virus infection

Mixed cryoglobulinemia is a systemic vasculitis with clinical manifestations ranging from the characteristic benign-appearing syndrome of palpable purpura, arthrologies, and fatigue to severe vasculitis involving vital organs. A strong association of the disease with hepatitis C virus infection and the demonstration of the specific concentration of the virus in the cryoglobulins have implicated hepatitis C virus in the etiopathogenesis of the disease. The increase in illicit intravenous drug use in the past 30 years seems to have raised the occurrence in the United States of this once uncommon disease and changed the demographics: there seem to be more male intravenous drug users in their forties with the disease than women without risk factors for hepatitis C virus infection in their fifties and sixties. Pathogenesis, therapy, and the hypothesis on the etiologic role of hepatitis C virus are reviewed, and the implications of recent studies and new concepts for treatment of this often benign-appearing but deceptive and potentially life-threatening disease are discussed.

Distribution of genotypes and response to alpha-interferon in patients with hepatitis C virus infection in Germany

To determine the distribution of hepatitis C virus (HCV) genotypes in German isolates, nucleotide sequences of the viral nonstructural 5 (NS5) genome domains were analyzed in isolates from 107 chronically HCV-infected patients. Of these 107 patients, 46 (43.0% were infected with subtype 1a and 47 (43.9%) with subtype 1b. Six patients (5.6%) with a history of intravenous drug abuse were infected with subtype 3a. Eight patients (7.5%) who had acquired their HCV infection in Egypt carried subtype 4a. Forty-three of the 107 patients were treated with alpha-interferon. Of these 43 patients, 16 (37.2%) were infected with subtype 1a and 27 patients (62.8%) with subtype 1b. Three patients infected with HCV-subtype 1a (18.7%) and four patients infected with subtype 1b (14.8%) showed a sustained complete response after interferon therapy. The HCV genotype 1 with its subtypes 1a and 1b was the most common source of HCV infection in this group of patients. There was no significant difference in response to alpha-interferon treatment of HCV infection with the subtypes 1a or 1b.

Interferon-alpha-2a. A review of its pharmacological properties and therapeutic use in the management of viral hepatitis

Interferon-alpha-2a is a recombinant interferon with antiviral, antitumour and immunomodulatory properties. Clinical studies have demonstrated that the drug offers therapeutic benefit in patients with some forms of chronic viral hepatitis. Remission, as measured by clearance of viral DNA and hepatitis B 'e' antigen (HBeAg), and normalisation of serum alanine aminotransferase levels, is observed in approximately 30 to 45% of patients with chronic hepatitis B receiving interferon-alpha-2a (2.5 to 18MU administered 3 times/week); about 5 to 15% of untreated controls remit spontaneously every year. Complete recovery [with loss of hepatitis B surface antigen (HBsAg)] is usually noted in < 20% of treated individuals. Similar response rates have been reported in the relatively small number of children evaluated to date. Although numerous studies have shown that interferon-alpha-2a (at various dosages) induces biochemical amelioration of chronic hepatitis C in approximately 50 to 75% of patients, relapse is common. Thus, long term remission may only be observed in about 15 to 30% of treated patients. On the other hand, this disorder remits spontaneously in only a few patients. The role of interferon-alpha-2a in the treatment of chronic hepatitis D remains unclear. Although preliminary data suggest it may be beneficial, cessation of therapy is generally followed by relapse. As with other types of interferons, most patients receiving interferon-alpha-2a experience an 'influenza-like' syndrome, which tends to diminish with continuing therapy. Other effects such as fatigue, lethargy, anorexia and weight loss are usually dose-limiting. Serum neutralising antibodies develop in approximately 10 to 20% of treated patients. Thus, although response rates are less than optimal, interferon-alpha-2a is a drug of first choice amongst the limited therapeutic options available for the management of well-compensated chronic viral hepatitis B or C.

Development of antiviral therapy with alpha interferons: promises, false hopes and accomplishments

This overview describes the development of interferon therapy in four different types of viral diseases. (1) Upper respiratory infections: despite extensive efforts interferons have not found a place in the treatment of these very common diseases. (2) Herpes keratitis: alpha interferons are highly active in combination therapy, but have gained only very limited clinical use. (3) Papillomavirus infections: alpha interferons have been approved for the treatment of papillomavirus infections of skin and mucous membranes and are in fairly wide clinical use. (4) Chronic hepatitis B, C and D: alpha interferons have become the treatment of choice and are used very extensively worldwide. The four examples illustrate both the clinical potentials and the limitations of alpha interferons and give some guidelines for future work. The overall conclusion is that chronic viral diseases lend themselves to interferon therapy more readily than acute viral infections. The general trend is toward the use of interferons in combination therapy.